Concept: The VSEPR theory helps predict the geometry of molecules based on the number of electron pairs around the central atom. Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds.

Why (A) is correct:

In PCl₅, the central phosphorus atom is bonded to five chlorine atoms. To accommodate these five bonds, the phosphorus atom undergoes sp³d hybridization. This hybridization leads to a trigonal bipyramidal geometry, where three chlorine atoms occupy equatorial positions and two chlorine atoms occupy axial positions.

Option Analysis:

• A) In PCl₅, P atom is sp³d hybridized and has trigonal bipyramidal geometry. This statement is correct. The phosphorus atom forms five sigma bonds, requiring five hybrid orbitals, which are formed by sp³d hybridization. The resulting geometry is trigonal bipyramidal.
• B) In PCl₅, all P–Cl bonds are of equal length. This statement is incorrect. In a trigonal bipyramidal geometry, the axial bonds are longer than the equatorial bonds due to greater repulsion from the equatorial bond pairs.
• C) In PCl₅, P atom is sp³ hybridized. This statement is incorrect. sp³ hybridization would result in four hybrid orbitals and a tetrahedral geometry, which is not the case for PCl₅.
• D) In PCl₅, the axial chlorine atoms are closer to central P atom than equatorial chlorine atoms. This statement is incorrect. As mentioned in option B, the axial bonds are longer than the equatorial bonds, meaning the axial chlorine atoms are farther from the central P atom.

Correct Answer: (A)